1. Field of the Invention
The present invention relates to detection of positions of tissues. More specifically, the present invention relates to a method for detecting positions of body tissues and an apparatus using the method.
2. Description of the Related Art
The deepening of a low birthrate and an aging phenomenon is acting as a catalyst in developing robotic industry. As the need for smart robots working instead of people increases, the worldwide robot market is rapidly expanding. The robots can be utilized in various fields, including operations in biologically dangerous regions like the scene of a fire, the reconnaissance in battlefield, and the lengthy surgery.
Among those robots, medical robots have been being developed focusing most on user convenience. The main principles in developing medical robots are to provide convenience in using to doctors, to provide no inconvenience to patients, to minimize invasions of patients, to minimize pains of patients, etc. The medical robot technology is a technic field combining BT (Bio-Tech), NT (Nano-Tech), RT (Robot-Tech), and MT (Medical-Tech).
The orthopedic surgery using a robot enables precise bone cutting. For this, there is a need to figure out positions of bones before surgery. It also needs to be figured out that whether the positions of bones have been changed during surgery, and how much the bones have been moved, if it has been changed.
During surgery, as methods for figuring out the positions of bones, there are method using anatomical shapes, method using the center of joints, method that matches a shape of bone that is obtained from medical images with a shape of bone exposed in surgery, etc.
However, after a step of bone cutting using a robot has started, when trying to figure out the positions of bones again before the step of bone cutting is finished, there is a problem that such methods cannot be used because the bone was amputated already.
After the bones has been moved, in order to figure out the positions of bones again, the existing surgery robots use a method that attaches extra markers (for example, screws or nails) to bones, and figures out the positions of bones again based on the positions of markers. Although such method is neat and quick, it causes damage to bones due to screws or nails that are inserted into bones.
Furthermore, because positions where markers can be attached without disturbing the surgery are limited, a recent minimally invasive surgery has problems that the amount of incision is increased in order to attach markers, and that the markers have to be attached through tissues.